The present disclosure relates to rotating devices such as the rotating portions of a food waste disposer grind mechanism.
There are many motor applications in which a motor's rotating member is subject to jams. This may be particularly common in applications such as water pumps, dishwashers, food processing equipment, food waste disposers, etc.
For example, food waste disposers are used to comminute food scraps into particles small enough to safely pass through household drain plumbing. A conventional disposer includes a food conveying section, a motor section, and a grinding mechanism disposed between the food conveying section and the motor section. The food conveying section includes a housing that forms an inlet for receiving food waste and water. The food conveying section conveys the food waste to the grinding mechanism, and the motor section includes a motor imparting rotational movement to a motor shaft to operate the grinding mechanism.
The grind mechanism that accomplishes the comminution is typically composed of a rotating shredder assembly with lugs and a stationary grind ring. The motor turns the shredder plate and the lugs force the food waste against the grind ring where it is broken down into small pieces. Once the particles are small enough to pass out of the grinding mechanism, they are flushed out into the household plumbing.
Grind mechanisms that utilize a fixed lug on the rotating shredder assembly are often susceptible to jams when grinding hard food waste, such as beef bones. The use of an induction motor may contribute to the probability of experiencing a jam because of its relatively low stall torque. To reduce the occurrences of jams, swivel, or rotatable, lugs that move out of the way before a jam can occur are employed. However, with swivel lugs, the energy displaced to the food waste is less and therefore can result in compromised grind performance and still lead to jams.
To free jams, some known systems use a technique that produces a pulsating torque from the motor when the disposer becomes “jammed”. Such a prior art technique is described in U.S. Pat. No. 3,970,907, which is incorporated by reference. The technique connects a diode in parallel across the start winding of a capacitor start motor to produce the pulsating torque. The parallel diode however, cannot be applied during starting. If it is, the motor will not be able to accelerate to full speed, and the capability of the disposer will be greatly reduced. It can only be applied after a jam of the grinding mechanism occurs. Because of the starting issue, the parallel diode is only connected when the consumer pushes a button located on the disposer assembly. Moreover, such known systems for freeing jams require user intervention—when the operator of the notices that the disposer is jammed, the pulsating torque must be activated by the user.
The present application addresses shortcomings associated with the prior art.